1. Field of the Invention
The present invention relates to an outboard motor including a catalyst and an exhaust gas concentration sensor.
2. Description of Related Art
An outboard motor according to a prior art is described in U.S. Patent Application Publication No. 2008/0022669A1. This outboard motor includes an exhaust device. Also, the exhaust device includes a catalytic converter (hereinafter, referred to as “catalyst”) which purifies exhaust gas and an oxygen sensor which detects a concentration of oxygen in exhaust gas. This exhaust device is arranged to purify exhaust gas of an engine by the catalyst and exhaust the exhaust gas into water from a boss of a propeller. This exhaust device is arranged to control an opening degree of an intake passage and a supply amount of fuel, etc., based on results of detection by the oxygen sensor so as to operate the engine with an air-fuel ratio which brings a high purification effect in the catalyst.